In an imaging system such as a camera, a solid-state imaging apparatus is arranged on a predetermined imaging plane of an imaging lens. The imaging lens forms an image of an object on an imaging region (an imaging area) of the solid-state imaging apparatus. The solid-state imaging apparatus generates an image signal corresponding to an object image. At this time, in an image signal generated by the solid-state imaging apparatus, when an amount of received light of surrounding pixels attenuates as compared with pixels near the center of the imaging region, a shading phenomenon may occur such that luminance (a signal level) of pixel signals around the imaging region attenuates as compared with that of the pixel signals near the center of the imaging region.